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  • 1.
    Do, Lan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    New tools for sample preparation and instrumental analysis of dioxins in environmental samples2013Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), two groups of structurally related chlorinated aromatic hydrocarbons, are of high concern due to their global distribution and extreme toxicity. Since they occur at very low levels, their analysis is complex, challenging and hence there is a need for efficient, reliable and rapid alternative analytical methods. Developing such methods was the aim of the project this thesis is based upon.

    During the first years of the project the focus was on the first parts of the analytical chain (extraction and clean-up). A selective pressurized liquid extraction (SPLE) procedure was developed, involving in-cell clean-up to remove bulk co-extracted matrix components from sample extracts. It was further streamlined by employing a modular pressurized liquid extraction (M-PLE) system, which simultaneously extracts, cleans up and isolates planar PCDD/Fs in a single step. Both methods were validated using a wide range of soil, sediment and sludge reference materials. Using dichloromethane/n-heptane (DCM/Hp; 1/1, v/v) as a solvent, results statistically equivalent to or higher than the reference values were obtained, while an alternative, less harmful non-chlorinated solvent mixture - diethyl ether/n-heptane (DEE/Hp; 1/2, v/v) – yielded data equivalent to those values.

    Later, the focus of the work shifted to the final instrumental analysis. Six gas chromatography (GC) phases were evaluated with respect to their chromatographic separation of not just the 17 most toxic congeners (2,3,7,8-substituted PCDD/Fs), but all 136 tetra- to octaCDD/Fs. Three novel ionic liquid columns performed much better than previously tested commercially available columns. Supelco SLB-IL61 offered the best overall performance, successfully resolving 106 out of the 136 compounds, and 16 out of the 17 2,3,7,8-substituted PCDD/Fs. Another ionic liquid (SLB-IL111) column provided complementary separation. Together, the two columns separated 128 congeners. The work also included characterization of 22 GC columns’ selectivity and solute-stationary phase interactions. The selectivities were mapped using Principal Component Analysis (PCA) of all 136 PCDD/F’s retention times on the columns, while the interactions were probed by analyzing both the retention times and the substances’ physicochemical properties.

  • 2.
    Do, Lan
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin. Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Dahl, Christen P
    Kerje, Susanne
    Hansell, Peter
    Mörner, Stellan
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Kardiologi.
    Lindqvist, Ulla
    Engström-Laurent, Anna
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Larsson, Göran
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Hellman, Urban
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    High Sensitivity Method to Estimate Distribution of Hyaluronan Molecular Sizes in Small Biological Samples Using Gas-Phase Electrophoretic Mobility Molecular Analysis.2015Ingår i: International Journal of Cell Biology, ISSN 1687-8876, E-ISSN 1687-8884, artikel-id 938013Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hyaluronan is a negatively charged polydisperse polysaccharide where both its size and tissue concentration play an important role in many physiological and pathological processes. The various functions of hyaluronan depend on its molecular size. Up to now, it has been difficult to study the role of hyaluronan in diseases with pathological changes in the extracellular matrix where availability is low or tissue samples are small. Difficulty to obtain large enough biopsies from human diseased tissue or tissue from animal models has also restricted the study of hyaluronan. In this paper, we demonstrate that gas-phase electrophoretic molecular mobility analyzer (GEMMA) can be used to estimate the distribution of hyaluronan molecular sizes in biological samples with a limited amount of hyaluronan. The low detection level of the GEMMA method allows for estimation of hyaluronan molecular sizes from different parts of small organs. Hence, the GEMMA method opens opportunity to attain a profile over the distribution of hyaluronan molecular sizes and estimate changes caused by disease or experimental conditions that has not been possible to obtain before.

  • 3.
    Do, Lan
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Geladi, Paul
    Haglund, Peter
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Multivariate data analysis to characterize gas chromatography columns for dioxin analysis2014Ingår i: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1347, s. 137-145Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Principal component analysis (PCA) was applied for evaluating the selectivity of 22 GC columns for which complete retention data were available for the 136 tetra- to octa-chlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). Because the hepta- and octa-homologues are easy to separate the PCA was focused on the 128 tetra- to hexa-CDD/Fs. The analysis showed that 21 of the 22 GC columns could be subdivided into four groups with different selectivity. Group I consists of columns with non-polar thermally stable phases (Restek 5Sil MS and Dioxin 2, SGE BPX-DXN, Supelco Equity-5, and Agilent DB-1, DB-5, DB-5ms, VF-5ms, VF-Xms and DB-XLB). Group II includes ionic liquid columns (Supelco SLB-IL61, SLB-IL111 and SLB-IL76) with very high polarity. Group III includes columns with high-percentage phenyl and cyanopropyl phases (Agilent DB-17 and DB-225, Quadrex CPS-1, Supelco SP-2331, and Agilent CP-Sil 88), and Group IV columns with shape selectivity (Dionex SB-Smectic and Restek LC-50, Supelco beta DEXcst, Agilent VF-Xms and DB-XLB). Thus, two columns appeared in both Group I and IV (Agilent VF-Xms and DB-XLB). The selectivity of the other column, Agilent DB-210, differs from those of these four groups. Partial least squares (PLS) regression was used to correlate the retention times of the tetra- to hexa-CDD/Fs on the 22 stationary phases with a set of physicochemical and structural descriptors to identify parameters that significantly influence the solute-stationary phase interactions. The most influential physicochemical parameters for the interaction were associated with molecular size (as reflects in the total energy, electron energy, core-core repulsion and standard entropy), solubility (aqueous solubility and n-octanol/water partition coefficient), charge distribution (molecular polarizability and dipolar moment), and reactivity (relative Gibbs free energy); and the most influential structural descriptors were related to these parameters, in particular, size and dipolar moment. Finally, the PCA and PLS analyses were complemented with linear regression analysis to identify the most orthogonal column combinations, which could be used in comprehensive two-dimensional gas chromatography (GC x GC) to enhance PCDD/F separation and congener profiling. (C) 2014 Elsevier B.V. All rights reserved.

  • 4.
    Do, Lan
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Liljelind, Per
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Zhang, Jin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Haglund, Peter
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Comprehensive profiling of 136 tetra- to octa-polychlorinated dibenzo-p-dioxins and dibenzofurans using ionic liquid columns and column combinations2013Ingår i: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1311, s. 157-169Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The orders of elution of all 136 tetra- to octa-chlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were determined on six gas chromatography (GC) columns. Three of these columns had ionic liquid stationary phases (SLB-IL111, SLB-IL76 and SLB-IL61; Supelco), one a liquid crystal phase (LC-50; Restek), one a chiral phase (beta DEXcst; Restek) and one a low bleed non-polar phase (DB-XLB; J&W/Agilent). According to our results, the high polarity and multiple solvation interactions of the ionic liquid stationary phases offered superior resolving power to that achieved with previously evaluated columns. The SLB-IL61 and SLB-IL111 columns resolved or partially separated 106 and 100 congeners, respectively, of the 136 PCDD/Fs. The SLB-IL61 also resolved 15 and partially separated one of the seventeen 2,3,7,8-substituted PCDD/Fs. Additional congeners can be separated by complementary analyses using additional columns in a dual- or triple-column approach. For example, using a combination of the SLB-IL61 and SLB-IL111 columns all but 8 congeners would be separated, including all 2,3,7,8-substituted PCDD/Fs. Two more congeners would be separated using a combination of SLB-IL76 and a liquid crystal (SB-Smectic) column, but in this case the 2,3,7,8-TeCDF would not be resolved. Three-column combinations would give even better separation: the DB-17/Smectic/SLB-IL76 and DB-225/Smectic/SLB-IL111 combinations would separate all but 1 of the 136 PCDD/F congeners. Unfortunately, the smectic column is no longer in production. If only commercially available columns are considered, combinations of SLB-IL61 and SLB-IL111 with DB-XLB, LC-50, or DB-225 offer the best performance, with 4, 4, and 3 unresolved congeners, respectively. Moreover, in each of these cases, one of the congeners in each unresolved pair is resolved on at least one of the other columns and so a reasonable estimate of the unresolved congeners' concentrations can be obtained by subtraction. The profiling of all 136 PCDD/Fs is thus greatly facilitated by using ionic liquid columns or combinations including such columns. However, there is room for improvement in the technical performance of the evaluated ionic liquid columns: their long-term retention time stability was poor and some highly chlorinated and sterically hindered congeners underwent dehalogenation during separation.

    (C) 2013 Elsevier B.V. All rights reserved.

  • 5.
    Do, Lan
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Lundstedt, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Haglund, Peter
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Optimization of selective pressurized liquid extraction for extraction and in-cell clean-up of PCDD/Fs in soils and sediments2013Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 90, nr 9, s. 2414-2419Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper describes the development of methods for selective extraction of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) from soils and sediments, using pressurized liquid extraction with in-cell clean-up (SPLE). Two binary solvent mixtures, viz. dichloromethane/n-heptane (DCM/Hp), and diethylether/n-heptane (DEE/Hp), were evaluated. The SPLE extraction conditions were optimized using central composite face (CCF) design. Three factors were investigated: extraction temperature (60-160°C), number of extraction cycles (1-3) and time per cycle (2-18min). The results showed that DCM/Hp (1/1, v/v) and DEE/Hp (1/2, v/v) were the best extraction solvent compositions and that the extraction temperature was a critical factor that needed careful optimization to achieve high extraction efficiency without co-extraction of sulfuric acid. Under the optimal conditions, the SPLE methods provided results with good accuracy and precision. For the sandy soil certified reference material (CRM-529) the quantification results ended up in the range 82-110% as compared to the concentrations obtained by a reference method based on Soxhlet extraction and external column clean-up. Furthermore, for a clay soil (CRM-530) and a sediment reference material (WMS-01), the accuracy (trueness) of the TEQ values were +11% (DCM/Hp) and +8% (DEE/Hp) for CRM-530, +8% and -7% for WMS-01, respectively. The individual congener concentrations also agreed well with the certified values. These findings show that SPLE is a promising method for combined extraction and clean-up of PCDD/Fs in soil/sediment samples.

  • 6.
    Do, Lan
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Xuan, Thong H.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Lundstedt, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Haglund, Peter
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Modular pressurized liquid extraction for simultaneous extraction, clean-up and fractionation of PCDD/Fs in soil, sediment and sludge samples2013Ingår i: Analytical Methods, ISSN 1759-9660, E-ISSN 1759-9679, nr 5, s. 1231-1237Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Modular pressurized liquid extraction (M-PLE) procedures were developed for simultaneous extraction, clean-up and fractionation of polychlorinated dioxins and furans (PCDD/Fs) in soil, sediment and sludge samples. The procedures utilize two coupled extraction cells: an upstream cell filled with the sample and layers of silica and acid- and base-modified silica, and a downstream cell filled with activated carbon. The silica layers were added to remove polar or hydrolysable matrix components, and the carbon to perform planarity-based fractionation. Two solvent systems (dichloromethane–heptane, DCM–Hp and diethyl ether–heptane, DEE–Hp) and two activated carbon loads (1% and 3% carbon on Celite) were evaluated using certified reference materials (CRM-529 and WMS-01) and materials from previous inter-calibration studies. Using any of the four procedures, data statistically equivalent to the certified or reference values were obtained. The M-PLE procedure using DCM–Hp and 1% carbon sometimes extracted the reference materials more efficiently than the reference methods, while the DEE–Hp procedure extracted them equally efficient, offering an alternative with less environmental impact. The methods with 1% carbon on Celite produced sufficiently pure extracts for sample loads up to one gram, but for greater sample loads the higher carbon load (3% carbon on Celite) was required to avoid breakthrough of target analytes. The new streamlined procedures are fast, cost-efficient, involve relatively low environmental impact (in the case of DEE–Hp) and are well suited for high-throughput analysis of solid samples, e.g. in connection with environmental monitoring campaigns and major soil remediation efforts.

  • 7.
    Do, Thanh Lan
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Lundstedt, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Haglund, Peter
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Selective pressurized liquid extraction of PCDD/Fs in soil: Optimization using experimental design2010Konferensbidrag (Refereegranskat)
  • 8. Kerje, Susanne
    et al.
    Hellman, Urban
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Do, Lan
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Larsson, Göran
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Kämpe, Olle
    Engström-Laurent, Anna
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Lindqvist, Ulla
    Is low molecular hyaluronan an early indicator of disease in avian systemic sclerosis?2016Ingår i: Connective Tissue Research, ISSN 0300-8207, E-ISSN 1607-8438, Vol. 57, nr 5, s. 337-346Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    AIM OF THE STUDY: To further elucidate the pathogenesis of systemic sclerosis (SSc) an experimental avian model was used. University of California at Davies line 200-chicken (UCD-200) spontaneously develops a SSc like disease that has most features of human SSc with vascular effects, inflammation, autoimmunity and fibrosis. The first signs of disease in UCD-200 are swelling and ischemic lesions of the comb, a tissue containing high amounts of the glycosaminoglycan hyaluronan. The aim was to evaluate inflammatory and fibrotic processes of the disease with regard to the molecular weight of hyaluronan.

    MATERIAL AND METHODS: Comb biopsies from UCD-200 and healthy White Leghorn (WL) chickens as controls at different ages were studied with histochemical localization of hyaluronan, hyaluronidase 1, CD3, IgY and collagen I and III. Hyaluronan molecular weight distribution was estimated with gas phase electrophoretic analysis.

    RESULTS: At 2 days of age hyaluronan was visualized in UCD-200 at the dermal part of the comb with no simultaneous staining of Hyal-1. In adult UCD-200 the comb skin was almost totally devoid of hyaluronan compared to WL of the same age. An increase of low molecular weight (LMW) hyaluronan was detected in comb tissue from UCD-200 at 1 day, 1, 2, 4 weeks in contrast to adult animals.

    CONCLUSIONS: An early inflammatory process involving LMW hyaluronan was confirmed as a possible profibrotic process. This indicates that hyaluronan might be an important participant in early inflammatory events of SSc in UCD-200 chicken and that disappearance of hyaluronan in skin predisposes to fibrosis.

  • 9.
    Kumar, A.
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Reumatologi.
    Do, Lan
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Reumatologi.
    Hellman, Urban
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Reumatologi.
    Forsblad-d'Elia, Helena
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Reumatologi.
    OVEREXPRESSION OF MACROPHAGE MIGRATION INHIBITORY FACTOR IN PATIENTS WITH ANKYLOSING SPONDYLITIS AND ITS RELATION TO SEX, INFLAMMATION AND TREATMENT2018Ingår i: Clinical and Experimental Rheumatology, ISSN 0392-856X, E-ISSN 1593-098X, Vol. 36, nr 4, s. 716-716Artikel i tidskrift (Övrigt vetenskapligt)
  • 10.
    Lorén, Christina
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Kardiologi.
    Dahl, Christen P.
    Do, Lan
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Kardiologi.
    Almaas, Vibeke M.
    Geiran, Odd R.
    Mörner, Stellan
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Kardiologi.
    Hellman, Urban
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Kardiologi.
    Low Molecular Mass Myocardial Hyaluronan in Human Hypertrophic Cardiomyopathy2019Ingår i: Cells, ISSN 2073-4409, Vol. 8, nr 2, artikel-id 97Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    During the development of hypertrophic cardiomyopathy, the heart returns to fetal energy metabolism where cells utilize more glucose instead of fatty acids as a source of energy. Metabolism of glucose can increase synthesis of the extracellular glycosaminoglycan hyaluronan, which has been shown to be involved in the development of cardiac hypertrophy and fibrosis. The aim of this study was to investigate hyaluronan metabolism in cardiac tissue from patients with hypertrophic cardiomyopathy in relation to cardiac growth. NMR and qRT-PCR analysis of human cardiac tissue from hypertrophic cardiomyopathy patients and healthy control hearts showed dysregulated glucose and hyaluronan metabolism in the patients. Gas phase electrophoresis revealed a higher amount of low molecular mass hyaluronan and larger cardiomyocytes in cardiac tissue from patients with hypertrophic cardiomyopathy. Histochemistry showed high concentrations of hyaluronan around individual cardiomyocytes in hearts from hypertrophic cardiomyopathy patients. Experimentally, we could also observe accumulation of low molecular mass hyaluronan in cardiac hypertrophy in a rat model. In conclusion, the development of hypertrophic cardiomyopathy with increased glucose metabolism affected both hyaluronan molecular mass and amount. The process of regulating cardiomyocyte size seems to involve fragmentation of hyaluronan.

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